Keg Testing Question

I recently bought two used cornies. I pressure tested one by bringing the pressure up to twenty pounds and placed a guage to monitor and over the next three days watched the pressure drop to eight pounds. Obviously a leak somewhere and will go through the usual procedures to figure out where it is.

The second keg I did the same bringing the pressure up to twenty pounds and placed a pressure gauge to monitor pressure. Over the last two days the pressure has only dropped one pound.

Here is the question. When you pressure check a corny should it be empty? The first keg was half fulll of water and the second one had about one gallon of water in it. Does having water in it effect the pressure? Will the pressure drop if you do?

Thanks for your help
TD

If there is liquid, it will drop. The water will absorb Co2.

If there is a leak, more liquid in the keg will cause a faster pressure drop, as there is a smaller volume of gas inside. Don't forget that temperature effects pressure too: A one PSI drop could just be due to lower temp, if it doesn't drop further.

The biggest change is going to come from temperature. Remember PV=nRT from high school? at different temps with the same volume, you're going to change the pressure. I wouldn't worry unless the pressure drop was a lot in a short period of time. I always pressure test with an empty keg, but that doesn't mean it's the best way to do it. Whatever method you prefer, use the same on all your tests so to keep consistency. My 2¢.

I pressure test with a little soap solution. I just squeze a rag with soapy water around the lid and poppies. If there is any leaks, you will easly see the bubbles.

I replace all of the seals on them before even testing them... who knows how old the ones that are in there are. They usually stink like soda syrup anyways.

finchlake said:

I pressure test with a little soap solution. I just squeze a rag with soapy water around the lid and poppies. If there is any leaks, you will easly see the bubbles.

Click to expand...

Star San works great for this, too. Plus it sanitizes, and doesn't get soap anywhere near the beer equipment!

Yes, water will absorb the CO2. More water, more pressure drop. You should test them dry.